In an act of Congress approved March, 1885, five additional vessels were authorized, and these, the _Charleston_, _Baltimore_, _Newark_, and gun-boats No. 1 and 2, are under construction.[49] Up to the time of the inception of these cruisers no steel for ship-plates had been rolled in the United States. Construction in American iron plates had been extensively carried on, but if steel plating was required it had to be imported at great cost to the builder. Those who contemplated bidding on the proposals issued by the government for the first four vessels had to consider this matter. Mr. John Roach, of New York and of Chester, Pennsylvania, undertook the manufacture of this material, and finding that success attended his experiment, he was able to direct extensively the steel-works at Thurlow, Pennsylvania, to this line of business, and when the bids were opened it was found that this new industry, introduced through his enterprise, enabled him to underbid all competitors. After receiving the contracts for the ships, Mr. Roach contracted with the Phœnix Iron Company, of Phœnixville, with Messrs. Park Brothers, of Pittsburgh, and the Norway Iron and Steel Works, of South Boston, for supplies of similar material: thus the first step in this effort to rehabilitate the navy resulted in introducing a new industry into the country. The still more extensive development of industries that will attend the work of rehabilitation as it advances will be treated further on. Before presenting the types of cruisers which are now to be introduced into the navy, it may be well to refer to an error that exists, or has existed, in the popular mind as to the signification of a steel cruiser. To many who are uninformed in technical language the word steel, in connection with a vessel of war, implies protecting armor, and such misapprehension would convey the idea that a cruiser of steel is able to contend with an armored vessel. This is a mistake; there is protection obtained by constructing a vessel of steel, but not such as is provided by armor. The destructive effect of shell-firing and the development in modern artillery have made armor necessary for all vessels which can carry it, and has also made it necessary to provide all other protection possible to vessels that cannot carry armor. Although this protection cannot be given absolutely to the hull of such ships and to the _personnel_, it is provided to the _buoyancy_ by the introduction of water-tight compartments and protective decks, which limit the destructive effect of the fire of the enemy and localize the water that may enter through shot-holes. With a wooden hull it would not be possible to combine this precaution because of the difficulty in making joints water-tight between wood and metal, and in consequence of the weight that would be added to a wooden hull, which is already from sixteen per cent. to twenty per cent. heavier than if constructed of steel.